Mechanical Turk shows how hard it is to draw a straight line

How hard is it to draw a straight line? It turns out to be more difficult than you think, as this video by artist Clement Valla demonstrates. He used Amazon's Mechanical Turk service to enlist the sketching skills of 500 people. Each was paid two cents to trace the drawing of the person before them, starting with a simple straight line, but small copying errors soon led to wildly different shapes.

You can see that someone makes a mistake right from the start, veering off sideways from the original straight line. This accidental wobble quickly grows in size, causing the line to start twisting and turning.

Eventually the line splits, and the separate parts go their own way, until a disruptive individual puts two fingers up with a great big "V". It doesn't survive for long, and the end result is a random pattern of squiggles.